Luke is hesitant to train her because, according to Jedi history, the chosen one always struggles with staying on the light side of the Force because of the chaotic power running through them. He’s afraid that she could become Vader 2.0. If he trains her to fight Kylo, and she turns dark, she would do way more damage to the galaxy than Kylo could ever dream of doing.

Rey is pissed at Luke because she guesses that he was her father and is angry at him for abandoning her. Luke turns to her and says “No, you are my father”.

Rey is the reincarnation of Anakin Skywalker. Luke went to the first Jedi temple to better understand how the process works. He learned that the spirit of the chosen one is reincarnated by the Force every time the universe is thrown out of balance, which apparently happens on a semi-regular basis (Anakin was hardly the first time the chosen one reincarnated). This is why she’s so crazy powerful with the Force (remember that Anakin blew up the Trade Federation donut ship by himself when he was like 8 years old).

Rey learns lightsaber skills, Force skills, and has a vision quest thing where she talks with Maz Kanata (unsure if it’s telepathy or just a dream) and Hayden Christenson. The latter tells her that she is him, but different, and there’s a quick scene where we see hundreds of other Force ghosts who are implied to be past chosen ones.

Rey feels Finn’s distress elsewhere in the galaxy and says she needs to go to him. Luke tells her about the time he felt his friends in distress and Yoda told him to stay and finish his training, and his disobedience led to pain. But then he says he isn’t Yoda, and has his own way of doing things, and tags along with her to go help.

Finn wakes up on a Resistance cruiser and is told by Poe that they’re already en route to the makeshift Republic homeworld in the wake of the capital planet being blown up by Starkiller Base.

Leia wants to lobby them to go to war.

The Republic is being led by an interim dictator named Lord Vikram (Benicio Del Toro), who was quickly put into power by the few senators still around to maintain order.

Starkiller’s destruction of the Republic core worlds caused a galactic communications disruption because everything was routed through those worlds, so Vikram is trying to reestablish contact and ensure the Republic doesn’t collapse into anarchy.